The present invention relates to a pipe coupling of the type comprising an elastomeric sealing sleeve which before assembly is oversized relative to an outside diameter of a set of pipes to be coupled; an annular housing which encloses the sealing sleeve, which defines a longitudinal axis, and which is split in the direction of the longitudinal axis to define a housing gap; and a clamping device coupled to the housing and operative to draw the housing together in a peripheral direction to narrow the housing gap.
DE-A-2,428,101 (or corresponding U.S. Pat. No. 3,877,733) as well as EP-A-0,447,955 (or corresponding U.S. Pat. No. 5,137,305) disclose pipe couplings of the type described above. In the disclosed couplings, the clamping device for the housing has two threaded bolts which are parallel to one another and which extend through two cylindrical clamping bolts. The latter are positioned in clamping brackets which are attached to the housing on either side of the housing gap, which is bridged by an insert. The clamping bolts are provided with through holes, in the internal threads of which the threaded bolts are screwed. The cylindrical head of each of the threaded bolts bears on a clamping bolt, and defines a hexagonal socket.
To draw the housing together, which of course presses the sealing sleeve against the pipe ends, large clamping forces are necessary. In addition, upon assembly of the pipe coupling, the clamping bolts and thus also the clamping brackets have to cover a relatively long distance toward one another. The result of this is that quite considerable bending forces can be transmitted via the clamping bolts to the threaded bolts screwed into the latter, which bending forces can lead to bending of the threaded bolts. Not only are clamping forces generated which act in the peripheral direction of the housing, but forces are also generated which act in the radial direction and have a troublesome effect on the satisfactory drawing-together of the housing and thus on uniform bearing of the sealing sleeve against the pipe ends.
DE-U-8,512,007 describes a pipe-fracture clamp with which a seal enclosing a leaking point of a pipeline is put against the pipe line in a sealing manner. In this known pipe-fracture clamp, brackets are attached to a housing on either side of a housing gap which extends in the longitudinal direction, and cylindrical clamping bolts run through the brackets. Clamping screws pass through the clamping bolts with clearance, and the clamping screws carry a nut which is supported on the other clamping bolt. The relatively large housing gap is covered by an insert.